Valve-gear



2 Sheets-Sheet 1.

(No Model.)

M. E. HALL".

VALVE GEAR.

Patented July 9 Qgw m N. PETERS, Mela-Lithographer, wmm w. 0.0.

2 Sheets-Sheet 2.

(No Model) M. E. HALL.

VALVE GEAR. No. 406,835. Patented July 9, 1889.

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UNITED STATES PATENT OFFICE.

MARTIN EhIIALL, OF THE UNITED STATES NAVY, ASSIGNOR OF ONE-HALF TO MARY C. HALL, OF LOIVELL, MASSACHUSETTS.

VALVE-G EAR.

SPECIFICATION forming part of Letters Patent No. 406,835, dated July 9, 1889.

Application filed March 7 1888.

To all whom it may concern:

Be it known that I, MARTIN E. HALL, of the United States Navy, have invented new and useful Improvements in the Valve-Gear of Steam-Engines, of which the following is a full, clear, and exact specification, reference being made to the accompanying drawings, in which like letters refer to like parts in all the figures.

My invention consists of improved mechanism for regulating the supply of steam through the valve of an engine or of cutting off such supply at varying points of the stroke of the engine when necessary to cause the en gine to run with uniform speed and with an economical use of steam.

Fg'gure 1 is a side view of my valve-gear and its governing devices. Fig. 2 is a longitudinal sectional plan of the same adapted and applied to a single-acting compound engine, in which the valve of the low-pressure cylinder is actuated by a separate fixed eccentric E of any ordinary type. Fig. 3 is a side View of the inner side of the grooved eccentric, the shifting-cam, and the valve-stem. Fig. 4 is a detached view of the shifting-cam; and Fig. 5

is a transverse section (on a reduced scale) through 2 .2, Fig. 3.

In the drawings, E represents the cut-off cam placed loosely. upon the shaft so as to turn freely thereon within the limits of action of the automatic governor. This cam is made to turn upon the shaft in one direction by the centrifugal force of suitable weights F, and in the other direction by thecentripetal tension of a spring G. Said weights, together with the actuating-spring and the accompanying mechanism, being common to many of the well-known automatic engines, they require no further description in this connection.

E is a disk rigidly attached to the shaft H. In the side of this disk E is an eccentric groove a,wide on the steam side. This disk,with its groove, I denominate a grooved eccentric.-

b is a valve-rod attached at one end of the valve C and extending through any suitable guide, as c. It engages with the groove (1 of the grooved eccentric by the pin cl, projecting from the valve rod Z2.

Serial no. 266,495. (No model.)

The ordinary well-known actuating-weights F, Fig. 2, are linked to the bolts 6, Fig. 4:, of the actuating-cam E, so that as the weights (pivoted to one of the crank-disks 7L2) fly out they increase the angular advance of the cam E a The operation of my invention is as follows: Steam being admitted to the valve chest through the steam-pipe as, it enters the cylinder B and gives motion to the shaft H through the piston A and its connecting-rod, and the engine moves at the desired speed. If from any cause-such as a decrease of the load upon the engine or an increase in the pressure of steam-the rotary "movement of the shaft should be accelerated, the free ends of the weights F would move outward by the centrifugal force against the tension of the spring G, and by means of the connecting-links advance the cut-ofi cam E so that part of its periphery is projected beyond the inner edge of the wide portion of the groove a of the disk E and against the end of the valve-rod b, moving the latter and the valve to which it is at tached sufficiently to instantly and entirely close the valve and out OK steam at the desired point in the stroke to reduce the speed to the proper limit. Should the pressure of steam be decreased or a greater load be applied to the engine, the sudden decrease of speed in the rotary movement of the shaft H 80 will permit the spring G to draw the weights inward again and to move the cam E" back again toward its former position, or partially or entirely out of action. In the latter case the valve would be actuated entirely by the grooved eccentric E. It will be seen that in this invention the Valve travels normally up to the point of cut-off, being actuated thus far by the grooved eccentric alone. Now, if the speed of rotation should be sufficient to advance the cam beyond the inner edge of the wide portion of the groove a,.the valve 7 rod 17 is suddenly impelled forward and the steam is cut off instantly, and thevalve held in that position until the invariable point of release is reached, when the outeredge of the groove a engages with the valve-rod b by means of the pin (Z to draw it back and cause it to resume its normal movement, so that the lead, release, and compression remain the same and invariable at all points of cut-off.

An ordinary eccentric may be used instead of the grooved eccentric, and the same actuating-cam E be used in connection therewith, as shown in Fig. 5, and the end of the valve-rod b may be keptin contact with the eccentric or cam, as the case may be, by the steam-pressure against the end of the valve.

It is the special object of this invention to attain a complete and instantaneous cut-off of steam with no change whatever in the lead, release, or compression." 1

Having thus described my invention, what I claim as new is The combination of Y a single valve and valve-rod, a crank-shaft, a grooved eccentric (whose groove is Widest on the steam side) rigidly secured thereto and directly actuating said Valve and valve-rod, whereby the admission,release, and compression are normallyand invariably controlled, and a cut-0E cam suspended loosely upon said crank-shaft and adapted to a rotary movement upon said shaft and connected with and operated by an automatic centrifugal governor, whereby steam is cut off at varying points of the stroke by the said valve without change in its other movements, substantially as described.

'MARTIN E. HALL. Witnesses:

J. T. B. BOGARDUS, A. M. WAY. 

